The present invention relates to a turbo component for a turbocharger, and more particularly, the present invention relates to a component suitable for a nozzle body which requires heat resistance, corrosion resistance, and wear resistance.
Generally, in a turbocharger attached to an internal combustion engine, a turbine is rotatably supported on a turbine housing connected to an exhaust manifold of the internal combustion engine, and several nozzle vanes are rotatably supported so as to surround an external surface of the turbine. Exhaust gas which flowed into the turbine housing flows into the turbine from the outside and is exhausted in an axial direction, while rotating the turbine in this process. By rotation of a compressor mounted on the same shaft as that of the turbine at the opposite side, air supplied into the internal combustion engine is compressed.
Herein, the nozzle vanes are rotatably supported on a ring-shaped component as it is called a nozzle body or mount nozzle. A shaft of the nozzle vanes penetrates through the nozzle body, and is connected to a link mechanism. As the link mechanism is driven, the nozzle vanes rotate, and the opening degree of a flow passage of exhaust gas flowing into the turbine is adjusted. The present invention relates to a turbo component provided in the turbine housing, such as a nozzle body (mount nozzle) or a plate nozzle mounted thereon. That is, the present invention relates to a turbo component which contacts exhaust gas and also contacts the other driving members such as nozzle vanes.
Such a turbo component for a turbocharger contacts exhaust gas, which is a high temperature corrosive gas, and is hence required to have heat resistance and corrosion resistance, and is also required to have wear resistance because it slides with nozzle vanes. Hitherto, therefore, the component was made of high Cr cast steel, or SCH22 grade steel specified in the Japanese Industrial Standard with Cr surface treatment to enhance corrosion resistance.
However, these materials are not only poor in machinability but are also expensive and production costs of the turbo component are high, and therefore, there was a problem in that recent requirements for lower costs were not satisfied.